X-Flight Quadcopter Drone - Power Problem

Thread Starter

Aleksandr Gonzales

Joined Jan 15, 2016
27
Good day!

I have this power problem regarding my drone, and my repair attempt sucks. Hehe. I messed with the 5V / GND pins, I have shorted them accidentally.

4.jpg

That is the original picture of the PCB before I attempted to repair. The U3 is AMS 1117 5.0V chip, which I believe should output around 5V. However, as I test it via a multimeter, it only outputs 1.87 - 2.0V. So I have removed it from the circuit and test it directly, and it outputs 4.5-4.8V. So can I assume that the chip is good?

Next I try testing capacitors nearby, no short to ground. The drone powers on, but in a low-low voltage. The battery is 7.4V 2S 25C.3.jpg

I forgot to clean the board and my skills sucks. Sorry. Hehe. The transistor, in U4, I believe is okay. I don't have any schematics with regards to this drone.
 

wayneh

Joined Sep 9, 2010
17,152
I have this power problem regarding my drone...
Let's back up and focus on what was wrong before your "repair". You mention the drone partially powers up but is starving for power, or was that after the short?

A capacitor can be tested for both capacitance and for ESR, which is the thing most likely to fail first. A short is bad but the lack of a short tells nothing.

Where does that yellow wire belong?
 

LowQCab

Joined Nov 6, 2012
562
"No user serviceable parts inside"

The Adventure is the Journey, not the Destination.
90% of your time in the RC Hobby is going to be figuring out how to build-in reliability.

1) Get a smaller, Precision-Soldering-Iron, and very-fine-gauge Rosin-Core-Solder.
2) Check every wire, ALL WIRES, for short to Ground or Batt., damaged insulation, Solder-Bridges, etc.
3) Repair Wiring / Solder-Joints as needed.
4) Take steps to insure that the problem can't happen again.
5) Replace Board.
6) Go fly.


NewBeeDrone Tool-Kit .......
https://newbeedrone.com/products/tool-kit?_pos=29&_sid=58c9c2ef8&_ss=r


Premium Stuff ......
Solder, DigiKey 473-1128-ND ~$31.35
Soldering Iron, DigiKey P2C-ND ~$58.00
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.
 

Thread Starter

Aleksandr Gonzales

Joined Jan 15, 2016
27
UPDATE: I removed the AMS 1117 LDO chip. Removed and replace also the SMD Transistor after it and the three capacitors.
As a replacement to the LDO chip, I have used a resistor with 68k Ohms (+). From 7.6V to 4.7V. It works, but my drone constantly flashing low battery status. Maybe because of the unstable 5V source from the resistor?
 
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